/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.dolphinscheduler.common.lifecycle;

import lombok.experimental.UtilityClass;
import lombok.extern.slf4j.Slf4j;

@Slf4j
@UtilityClass
public class ServerLifeCycleManager {

  private static volatile ServerStatus serverStatus = ServerStatus.RUNNING;

  private static long serverStartupTime = System.currentTimeMillis();

  public static long getServerStartupTime() {
    return serverStartupTime;
  }

  public static boolean isRunning() {
    return serverStatus == ServerStatus.RUNNING;
  }

  public static boolean isStopped() {
    return serverStatus == ServerStatus.STOPPED;
  }

  public static ServerStatus getServerStatus() {
    return serverStatus;
  }

  /**
   * Change the current server state to {@link ServerStatus#WAITING}, only {@link ServerStatus#RUNNING} can change to {@link ServerStatus#WAITING}.
   *
   * @throws ServerLifeCycleException if change failed.
   */
  public static synchronized void toWaiting() throws ServerLifeCycleException {
    if (isStopped()) {
      throw new ServerLifeCycleException("The current server is already stopped, cannot change to waiting");
    }

    if (serverStatus == ServerStatus.WAITING) {
      log.warn("The current server is already at waiting status, cannot change to waiting");
      return;
    }
    serverStatus = ServerStatus.WAITING;
  }

  /**
   * Recover from {@link ServerStatus#WAITING} to {@link ServerStatus#RUNNING}.
   */
  public static synchronized void recoverFromWaiting() throws ServerLifeCycleException {
    if (isStopped()) {
      throw new ServerLifeCycleException("The current server is already stopped, cannot recovery");
    }

    if (serverStatus == ServerStatus.RUNNING) {
      log.warn("The current server status is already running, cannot recover form waiting");
      return;
    }
    serverStartupTime = System.currentTimeMillis();
    serverStatus = ServerStatus.RUNNING;
  }

  public static synchronized boolean toStopped() {
    if (serverStatus == ServerStatus.STOPPED) {
      return false;
    }
    serverStatus = ServerStatus.STOPPED;
    return true;
  }

}
